public class Test {
    public static void main(String[] args) {
        SingleLinkedList singleLinkedList = new SingleLinkedList();
        singleLinkedList.addFirst(1);
        singleLinkedList.addFirst(2);
        singleLinkedList.display();// 2,1
        singleLinkedList.addLast(2);
        singleLinkedList.addIndex(1, 0);
        singleLinkedList.addIndex(1, 2);
        singleLinkedList.addIndex(2,999);
        singleLinkedList.display();
        singleLinkedList.removeAllKey(2);
        singleLinkedList.display();
    }
}
